Organic acidurias: impact of age at onset and NBS

The information of 567 patients with organic acidurias (OADs) from the E-IMD registry were analysed using recursive partitioning of diagnostic and therapeutic strategies, and odds ratios (OR) for health outcome parameters. Different OADs were included in this study: methylmalonic (MMA, n=164), propionic (PA, n=144), isovaleric (IVA, n=83), and type 1 glutaric aciduria (GA1, n=176).

Of all OAD patients 71 % remained asymptomatic until day 8. Patients identified by newborn screening (NBS) had a significantly lower median age of diagnosis (8 days) compared to the late onset, (LO) group, but not compared to the early onset (EO) group (where EO represents patients presenting with symptoms during, while LO after, the newborn period).

This study concluded that NBS is an effective intervention to reduce time until diagnosis especially for LO patients and to prevent irreversible cerebral damage in GA1 and MMA-Cbl-. For other OADs, the clinical benefit of NBS was less clear. Moreover, the vast diversity of therapeutic interventions made it impossible to draw conclusions about optimal treatment.